Solar Panel in SIAB
This section describes the different parts of the portable solar panel system in SIAB that combine to overcome the basic infrastructural barrier ‘access to electricity’ in rural India and SSA.
In particular it highlights the importance of the ‘MPPT Quick Charging Controller’ with ensures the maximum charge rate for the 12 volt lithium battery included in the pack.
The portable solar panel folds down to the size of a laptop computer and weights just 1.80 kg or 3.97 lbs. The covering fabric is water resistant covered with a PU coating. It is an ideal choice for inclusion in the SIAB toolkit as there are no on site security issues due to its small size as it fits easily into the secure PELI (wheeled) box.
MPPT Quick Charging Controller
The MPPT (Maximum Power Point Tracking) is a key technology to harvest the maximum amount of energy from a solar panel. As sunlight intensity varies depending on the climate, time of the day, and seasonal change, the output voltage and output current of the solar panel under the sun also changes.
The output power from a solar panel is the mathematical product of its output voltage and output current. Typically, it takes a sophisticated digital signal processor (DSP) to try, sample, and calculate many operating voltage and current combinations before a maximum power point is identified. This kind of perturb-and-observe MPPT algorithm is time-consuming and in many cases, may lock into incorrect operating point. In contrast, iSolar uses an advanced analog MPPT algorithm. It does rely on conventional perturb-and-observe time-consuming method. It locks in the maximum power point in less than 1000th of a second. With this ultra-fast MPPT algorithm, the iSolar charger can spend 99.9% of the time charging the battery and harvesting the maximum power possible from the solar panel.
It uses only 0.1% of the time updating the present sunlight condition and re-calculating the maximum power point. As illustrated below, iSolar MPPT can track the maximum power combination of 17.5V and 3.05A (53.4W).
12 Volt Lithium Battery
The 12 volt lithium battery is the same type of battery used to power general notebook computers. With output power of 60W it can power the connected system, the iPad2, Pico projector and Speakers over a five hour period. It also comes with a 5 volt USB port.
Other Standard Accessories
Other standard accessories include DC to AC Inverter (100W) and a Car lighter plug with a 5V/!A USB port.